Taboni Anna, Barilari Caterina, Vinetti Giovanni, Fagoni Nazzareno, Ferretti Guido
Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy.
Eur J Appl Physiol. 2025 Apr;125(4):957-966. doi: 10.1007/s00421-024-05657-2. Epub 2024 Dec 3.
The mechanisms of oxygen uptake ( ) slow component in the severe exercise intensity domain are still a matter of debate. We tested the hypothesis that the rate of blood lactate ([La]) accumulation above maximal lactate steady state (MLSS) is a major cause of slow component.
On 13 males exercising on a cycle-ergometer, we measured gas exchanges, heart rate, and [La] during maximal incremental exercise test to determine maximal aerobic power ( ) and at constant power exercise tests at 60%, 65%, 70%, and 80% of .
Maximal was 3.19 ± 0.37 l·min, was 283 ± 28 W. At 60% all variables attained steady state in all subjects. Power at MLSS was 177 ± 21 W. At 80% a clear slow component was observed in all subjects, exercise lasted 11.3 ± 3.1 min and [La] was 7.4 ± 2.2 mmol at 5 min and 11.5 ± 3.6 mmol at 10 min. The energy balance computed at 80% resulted compatible with the principles of the energetics of muscular exercise, if we assume linear [La] increase, and thus constant metabolic power provided by [La] accumulation. Conversely, the metabolic power provided by slow component increases with time. This contrast is incompatible with the tested hypothesis that consequently must be rejected.
This study excluded [La] accumulation as a main cause of slow component.
在剧烈运动强度范围内，摄氧量（ ）慢成分的机制仍存在争议。我们检验了以下假设：高于最大乳酸稳态（MLSS）时血乳酸（[La]）的积累速率是 慢成分的主要原因。
对13名在功率自行车上运动的男性，我们在最大递增运动试验中测量气体交换、心率和[La]，以确定最大有氧功率（ ），并在 的60%、65%、70%和80%的恒定功率运动试验中进行测量。
最大 为3.19±0.37 l·min， 为283±28 W。在60% 时，所有受试者的所有变量均达到稳态。MLSS时的功率为177±21 W。在80% 时，所有受试者均观察到明显的 慢成分，运动持续11.3±3.1 min，5 min时[La]为7.4±2.2 mmol，10 min时为11.5±3.6 mmol。如果我们假设[La]呈线性增加，从而由[La]积累提供恒定的代谢功率，那么在80% 时计算的能量平衡与肌肉运动能量学原理相符。相反， 慢成分提供的代谢功率随时间增加。这种差异与所检验的假设不相符，因此该假设必须被拒绝。
本研究排除了[La]积累是 慢成分的主要原因。
